Silent Chiari Type I Malformation Presenting With Markedly Asymmetrical Papilledema Detected on Routine Ophthalmic Examination: A Pediatric Case Report.

Chiari type I malformation (CMI) is a congenital hindbrain anomaly that may disrupt cerebrospinal fluid (CSF) dynamics and lead to intracranial hypertension. Although papilledema is a well-recognized manifestation of elevated intracranial pressure, it is typically bilateral and symmetric. Asymmetrical papilledema is uncommon, particularly in pediatric patients, and may pose a diagnostic challenge. We report a 10-year-old boy with no neurological or visual complaints who was referred after asymmetrical optic disc edema was detected during a routine ophthalmic examination. Visual acuity was preserved bilaterally; however, fundus examination revealed mild papilledema in the right eye and pronounced papilledema in the left eye. Optical coherence tomography demonstrated markedly asymmetric thickening of the peripapillary retinal nerve fiber layer. Neuroimaging revealed a CMI associated with severe triventricular hydrocephalus. The patient underwent endoscopic third ventriculostomy, resulting in gradual resolution of papilledema. Despite preserved visual acuity, secondary optic atrophy developed in the initially more severely affected eye, defined clinically by optic disc pallor and supported by retinal nerve fiber layer thinning on optical coherence tomography. This case highlights that silent CMI with hydrocephalus may present solely with markedly asymmetrical papilledema in an otherwise asymptomatic child. Routine ophthalmic examination can play a pivotal role in the early detection of clinically occult but potentially vision-threatening intracranial pathology.